NEET-XII-Physics
01: Electric Charges And Fields
- #24Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude 17.0 × 10-22 C/m2. What is E: (a) in the outer region of the first plate, (b) in the outer region of the second plate, and (c) between the plates?
Ans : The situation is represented in the following figure.
A and B are two parallel plates close to each other. Outer region of plate A is labelled as I, outer region of plate B is labelled as III, and the region between the plates, A and B, is labelled as II.
Charge density of plate A, σ = 17.0 × 10-22 C/m2
Charge density of plate B, σ = -17.0 × 10-22 C/m2
In the regions, I and III, electric field E is zero. This is because charge is not enclosed by the respective plates.
Electric field E in region II is given by the relation,
Where,
`` \epsilon``0 = Permittivity of free space = 8.854 × 10-12 N-1C2 m-2
∴
= 1.92 × 10-10 N/C
Therefore, electric field between the plates is 1.92 × 10-10 N/C.